Potential of Carotid Ultrasonography in the Diagnosis of Coronary Artery Disease

BACKGROUND AND PURPOSE: Carotid artery atherosclerosis has been shown to correlate with coronary artery disease (CAD). This study evaluates the capacity of duplex ultrasonography of the carotid arteries as a tool in the diagnosis of CAD in comparison with exercise stress test and variance ECG. METHODS: Carotid ultrasonography, exercise stress test, and variance ECG were performed in 184 symptomatic patients evaluated with coronary angiography. The diagnostic capacity of the studied noninvasive methods was assessed by use of receiver operating characteristic (ROC) curves constructed by successive consideration of several cut points, such as (1) the presence of unilateral/bilateral plaques and (2) cross-sectional common carotid artery (CCA) intima-media (IM) area from 10 to 30 mm2 for ultrasonography; (1) ST depression > or =0.1 mV and > or =0.2 mV with and (2) without chest pain for exercise test; and electrical variability index from 50 to 100 for variance ECG. RESULTS: Coronary angiography revealed the presence of CAD (> or =50% luminal stenosis in 1 or more major epicardial arteries) in 147 patients (80%). Identification of carotid plaques on one or both sides and calculation of the left-sided (but not right-sided) CCA IM area provided a significant discrimination (P<.001 and P<.01, respectively) of patients with CAD. The discriminating capacity of the ultrasound procedures was equal to that of variance ECG and exercise test with ST depression criterion only but somewhat lower than that of exercise test with the combined chest pain and ST depression criterion (P<.05). However, at the chosen cut points, carotid plaque identification offered higher sensitivity than exercise test with either criterion (P<.01 and P<.001, respectively). CONCLUSIONS: Carotid ultrasonography is a useful diagnostic method that is comparable to exercise test and variance ECG for detection of CAD in a high-prevalence population.